Interesting -- none of the major VMWare customers had a second/alternative vendor/product? I hope they learnt the lesson.

The ecosystem existed - Red Hat OVE, Nutanix were mature in the enterprise market, but VMware had such a grip with low cost (honestly, it was a smart Broadcom play despite infuriating customers), ease of use, feature rich, big software/support/consultant ecosystem. It was almost like the Windows of virtualization, in that it bred complacency.

I know nothing about Tesco, but sometimes ops cultures lack the skills or mandate to successfully switch tech stacks.